Some telephone systems now offer a personal communication service (PCS) to their subscribers. As shown in FIG. 1, a PCS server PCS-SERV of a personal communication system comprises a PCS destination profile memory DP-MEM storing in association with at least one personal telephone number PTN a number M of destination profiles DPm respectively consisting of an ordered sequence of destination numbers PDNn indicating a number N of predetermined destination locations. A PCS routing means PCS-RM is provided for completing an incoming call directed to a set PTN by routing the incoming call sequentially to each destination location in accordance with the sequence indicated in the respective destination profile until a call is abandoned or answered. That is, if a PTN call is directed to the PCS routing means, a destination number PTN from an active destination profile is requested and the active destination profile, e.g. DP1, then provides sequentially the destination location numbers PDN11, PDN21, PDN31 . . . PDNN1 to the PCS routing means according to the predetermined sequence as indicated by the entry in the left hand column of the respective active destination profile, e.g. DP1.
Various operation principles can be used for the interaction between the PCS routing means PCS-RM and the destination profile memory DP-MEM when routing the call to the predetermined destination locations.
That is, when a call is delivered to the selected destination as indicated by the destination number PDN and the call is not answered in a predetermined period of time, then the call is removed from that destination, the destination profile memory DP-MEM provides the next destination location number PDN and the call is delivered to the next destination location in the predetermined sequence as indicated in the active destination profile DP. This relates to the situation where a single PTN call is directed to the PCS server PCS-SERV and the call is sequentially routed to the individual destination locations. In this case, once the PTN call has been accepted for processing by the PCS routing means PCS-RM, the personal telephone number PTN associated to the PCS subscriber is marked busy and no further possibly simultaneous PTN call is processed.
Alternatively, there is the possibility that several simultaneous calls directed to the same PTN number are processed at the same time. If one PTN call has already been delivered to a destination location, then this destination location is busy either because the PTN call is pending there or is actually be answered (i.e. the call has been completed to the called party at this destination location). If a further PTN call is directed to the same destination location which is now busy, the further PTN call is delivered to the next destination in the sequence as indicated by the active destination location profile. Thus, even a number of simultaneous incoming PTN calls can be sequentially routed or distributed (i.e. delivered) according to the same active destination profile until all incoming PTN calls are being answered or delivered.
An example of a personal communication system using such an active destination profile for the routing of a single incoming call is shown in FIG. 2. As shown in FIG. 2 each of the destinations 1, 2, . . . , n−2, n−1, N is associated with a specific destination number PDN respectively relating to the user desk telephone, a DECT telephone, a GSM mobile telephone, a home telephone or a voice mail system. A personal telephone number PTN “913392872” has been provided to the PCS subscriber and any incoming call directed to this personal telephone number is sequentially routed to the user desk telephone, the DECT telephone, the GSM mobile telephone, the home telephone and the voice mail system until the call is answered by the called party at one of the destination locations.
There are various possibilities how such a personal communication service PCS can be implemented e.g. by a telephone system. The personal communication service may be provided in a private environment like a private branch exchange PBX or a PBX network. The personal communication service can also be implemented in a public environment, e.g. provided as an intelligent network IN service in a fixed telephone network or a mobile radio telephone network. Depending on the implementation the PCS server may have different locations. The PCS server may be integrated in the exchange software or located in an external device connected to the exchange. The PCS server may also be distributed amongst all nodes or provided by a specific node in the telephone system. If it is distributed over the number of nodes, the PCS server does not have a specific predetermined location.
Furthermore, the PCS routing means, which is responsible for completing an incoming call directed to the personal telephone number PTN by routing the incoming call sequentially to each destination location indicated in an active destination profile, can be implemented in various ways. One possibility is that the PCS routing means PCS-RM sets up a basic call to the determined destination location once the destination number PDN has been provided by the destination profile memory DP-MEM. In this case, a new call will be set up to each destination location sequentially. Alternatively, the PCS routing means PCS-RM can activate a service (provided by the network) which allows a call forwarding.
The principles of using different call distribution criteria for distributing calls in association with destination profiles according to the invention (as explained below) can be implemented independent of the scenario of the location and the routing method used by the PCS server of the personal communication service PCS. Hereinafter, a few examples of implementations of the personal communication service PCS to which the invention can be applied are discussed with reference to FIGS. 3a–d. 
FIG. 3a is an example of a PCS server integrated in a private branch exchange (PBX) software. The PCS application (the PCS software and data base) implemented in association with the user profile DP (e.g. included in the PCS-MEM) receives the dialed PTN number in step S2 from the PCS routing means PCS-RM after the PCS-RM receives the dialed user number from the calling user in step S1. More specifically, a call monitor means CM of the PCS routing means PCS-RM forwards the PTN number to the PCS application. The PCS application returns the selected destination in step S3 according to the active destination profile. In step S4 the routing means PCS-RM distributes the call to the selected destination.
FIG. 3b is an example of a PCS server integrated in a PBX software in case of a network call. In step S1 a calling user dials the PTN user number which is directed to the first exchange PBX1 of the PBX network. The user associated with the dialed user number has a subscription in the exchange PBX2. Therefore, in step S2 the dialed user number is directed to the exchange PBX2. In the exchange PBX2 the call monitoring unit of the PCS routing means returns in step S3 the selected destination according to an active destination profile. In step S4 the call is distributed to the third exchange PBX3 where the selected destination is connected. In this case the selected destination is not connected to the first exchange PBX1 to which the call was first routed in step S1. Therefore, the selected destination number is returned to the first exchange PBX1 and the call routing or call forwarding is started from the first exchange PBX1. In FIG. 3b the PCS routing means can be viewed as being provided in the first exchange PBX1 whilst the call monitoring unit of the PCS routing means as well as the destination profiles are provided in the second exchange PBX2.
FIG. 3c shows an example of a PCS server integrated in the software of a home location register HLR in a public land mobile network PLMN. A calling user, e.g. from a fixed network PSTN, dials a user number in step S1 which is received by the gateway switching center GMSC of the mobile network. The GMSC provides the dialed user number in step S2 to the home location register HLR. The PCS server implemented in the home location register HLR receives the dialed user number and returns in step S3 the selected destination according to the active destination profile. The HLR returns the information to the GMSC to route the call to the selected destination MSC/VLR in step S4. In this case the PCS destination profile memory can be visualized as being incorporated in the home location register HLR whilst the PCS routing means uses the facilities provided by the GMSC for routing the call to the predetermined destination location number.
FIG. 3d is an example of an implementation of a PCS server as part of the intelligent network. A service switching point SSP receives in step S1 the dialed user number from the fixed network PSTN (Public Switch Telephone Network) and sends it in step S2 to the service control point SCP. In the service control point SCP the PCS application receives the dialed number and returns the selected destination in accordance with the destination profile. In step S3 the destination to distribute the call is provided to the service switching point SSP and in step S4 the service switching point SSP routes the call to the selected destination, e.g. to a gateway mobile switching center of a PLMN network, if the selected destination is part of such a mobile network PLMN. In this case, the PCS destination profile memory can be provided by the service control point SCP whilst the PCS routing means is implemented by parts of the service switching point SSP and the respective networks used for routing the call, e.g. by the GMSC of the PLMN.
As explained above, the present invention can be used for any implementation of the PCS server, e.g. in the scenarios shown in FIGS. 3a–3d. However, also other implementations are possible in accordance with the network configuration and the routing facilities. In this connection, several factors may be considered in a personal communication system PCS, e.g. the time spent by the PCS until the call is completed (answered by the called user or other), how easy and flexible the PCS can be configured, the amount of system resources spent by the PCS server to locate the called user and to route the call there, etc.